Motor vehicles are equipped with air bag systems that are electrically activated in the event of a vehicle crash. The activation of the air bag systems is generally accomplished by way of impact sensors strategically positioned in various places about the vehicle.
It is known that an adaptive restraint system can be accomplished by using weight sensors to determine the weight characteristic of the seat's occupant. By determining the relative weight of the occupant, the force of deployment for the air bag can be determined. However, it is possible that the seat's occupant may be quite heavy and still be small in size, which requires different deployment forces than a larger, lighter occupant. Likewise, it is important to distinguish between a human occupant and an inanimate object in determining air bag deployment.
Sensors to detect the mere presence of a seat occupant are also known. For example, capacitive sensors have been used to detect the presence of a human occupant in the seat in order to determine air bag deployment forces. However, capacitive sensors merely detect the presence of a human occupant and cannot distinguish between a small occupant and a large occupant, nor can the capacitive sensor distinguish between a heavy occupant and a light occupant.